Wrench



ec. 10, 1935. F. J. KRAUSE 21,023,733

WRENCH Filed June 20, 1935 8 INVENTOR i f m BY v Patented Dec. 10, 1935 UNITED STATES PATENT OFFICE WRENCH Ware Application June 20, 1933, Serial No. 676,613

2 Claims. (Cl. 81177) This invention relates to wrenches and has for its primary object the provision of a wrench which is particularly useful for tightening the nuts of flange bolts of closely grouped return bends such as employed in tube economizers.

In tube economizers, in order to obtain the necessary velocity of the heating gases to secure efficient heat transfer, the tubes must be closely spaced. This results in bringing the return bends close together and in their having relatively sharp bends, which introduces dilficulties in detachably securing the flanges of the return bends and economizer tubes together. To meet this situation it has been the practice to employ return bends of difierent lengths in alternation, i. e., to make every other return bend much longer than the other so as to provide a large space for the insertion of a spanner wrench between the short and long bends to enable turning of the flange securing nuts, such construction being shown in the Trainer, et a1, Patent No. 1,818,769.

The above increases the costs of the economizers because two sizes of bends must be employed and excess material not otherwise necessary, is used. In addition, added end space is needed to accommodate the longer return bends.

It is one of the objects of my invention to make it possible to employ return bends all of one size and shape in tube economizers and like devices, and to the accomplishment of this end I have provided a novel wrench of such construction that it may be readily inserted between these return bends for access to the flange nuts.

How the foregoing, together with such other objects and advantages as may hereinafter appear or are incident to my invention are realized, is illustrated in preferred form in the accompanying drawing, wherein- Figure l is a fragmentary end viewillustrating the arrangement of return bends in an economizer with a wrench constructed in accordance with my invention applied to one of the flange nuts;

Figure 2 is a plan View taken in the direction of the arrows 2-2 in Figure 1 illustrating my wrench applied toone of the nuts and also in instance all of the return bends are of uniform size and shape, 1. e., the legs 3 of all of the bends are of the same length and the connecting portions fall in a line as viewed in Figures 2 and 3. Such an arrangement is very desirable not only from the viewpoint of manufacturing costs, which are reduced because of the elimination of different sizes of bends in the same economizer, but also in that it enables the width of the economizer to be reduced.

However, in order to construct an economizer in this manner, provision must be made for gaining access to the flange nuts 4 which are located within the U of the return bends, it being noted that by employing return bends all of one size and shape the space ordinarily provided by making alternate bends longer than the others for the insertion of a spanner wrench, no longer exists. I have therefore provided a novel wrench which is peculiarly adapted to the tightening of the nuts in such economizers.

My improved wrench comprises a shank portion 5, a nut engaging portion 6 having a hexagonal hole therein, a head portion 1 and a portion 3 connecting the shank and nut engaging portions. The shank portion 5 is preferably round in cross section and of a diameter less than the spacing of the return bends, and the nut engaging portion 6 is disposed at right angles to the shank and also of a thickness less than the spacing of the return bends. As used in the specification and claims this term thickness refers to the dimension of the nut engaging portion 6 in a direction along the axis of the nut receiving aperture.

However, this alone does not accommodate the wrench for application to the nuts, for provision must be made to work the angularly disposed nut engaging portion into the U of the bends and this must be done without reducing the shank and nut engaging portions to the point where the wrench would be too weak to be practical. I have therefore formed that portion of the wrench which is adjacent the nut engaging portion, i. e., the portion 8 which connects the shank 5 and portion 6, in a special and novel manner which permits of ready insertion of the wrench and at the same time provides the necessary strength.

By referring particularly to Figures 2, 3 and 4, it will be seen that this connecting portion 8 is in ofiset and recessed relation to the shank to enable the tube to seat or nest in this portion when the wrench is in the act of being inserted. This is clearly shown in dot and dash. lines in Figure 2. This portion of the wrench is also elongated in cross section as shown in Figures 3 and t for strengthening purposes and the corner 9 is rounded to facilitate entry of the wrench. The length of the portion 8, while of a length sufiicient to readily insert the wrench, is short enough so as not to interfere with adjacent parts when tightening the nuts, and thereby maximum turning movement is secured. This is the reason why the shank proper is preferably made round. In

this connection it is to be noted that by offsetting the portion 8, the center line of the shank is kept close to the center line of the nut aperture of the wrench.

The head I may be provided with apertures IQ for the reception of a bar or handle for tightening the nuts.

It will be seen from the foregoing that I have provided -a novel wrench which makes it possible to construct devices such as tube economizers having closely spaced tubes in a very desirable manner.

I claim: 7

1. A wrench for tightening flange nuts of closely grouped return bends which are so disposed as to beinaccessible to wrenches of standard form, comprising a straight shank, round in cross section and of less diameter than the spacing between adjacent return bends, a nut engaging portion at one end of the shank disposed at right angles to the shank of less thickness than the spacing between adjacent return bends, and a portion offset outwardly with relation to the shank for connecting the shank and nut engaging portion, said offset portion being of elongated flattened cross section with its smallest dimension less than the spacing between adjacent return bends and being in its length and 5 in its end portions which merge into said shank and nut engaging portion of such configuration and dimensions as to pass between adjoining return bends with a turning movement and permit engagement with the flange nuts of the re- 10 turn bends.

2; A wrench for tightening flange nuts of closely grouped return bends which are so disposed as to be inaccessible to wrenches of standard form, comprising a straight shank of less 15 diameter than the space between adjacent return bends, a nut engaging portion at one end of the shank disposed at right angles to the shank and of a thickness less than the space between return bends, and a portion of elongated flattened 20 cross section for connecting the shank and nut engaging portion outwardly offset with relation to the shank, said portion being of a thickness 

